The pump head contains a pressure switch that turns off the pump when the pressure is reached. In typical operation the pump would be always powered but the pressure switch will hold it off until a faucet or valve is opened and water starts to flow. You can make adjustments to the pressure cutoff; on your pump the adjustment appears to be performed by turning the screw on the end of the pump (clockwise for more pressure, counterclockwise for less).

Where you might run into a problem is when your flow is much less than the 3 liters/minute that the pump is designed for. This will cause the pump to cycle on and off rapidly which is a generally undesireable situation. You can remedy this to some extent by adding an "accumulator" downstream of the pump; this is a small tank, partially filled with air, that would act as a buffer between the pump and misting heads so the cycling occurs less frequently.

Another option is to drive the pump using a mosfet and PWM. Basically just reduce the current to the pump so it cannot generate as much pressure.

Do you have a link to documentation on your misting system? Just curious what you're using.

Jason_B

My name is Jason and I work in product development at CO2meter.com. I try to keep up with forums for arduino and other similar products to provide guidance to projects that involve air quality control. We have clients that run large scale mushroom growing operations, and along with Temperature and humidity, it is also important to monitor CO2 levels. This article explains a little about why: http://www.co2meter.com/collections/mushrooms-co2.

It lists a few products that we often provide for our clients, but to incorporate into an automated system I would look into the Cozir RH/T http://www.co2meter.com/collections/co2-sensors/products/cozir-0-2-co2-sensor. This provides real time CO2 level, Temperature, and humidity over UART. I have written some basic libraries to work with MCUs and getting it running on an arduino is very straightfoward.

If you have any questions or would like the code for running these please let me know.